212 
stated, the most striking characters of this 
plant are as follows: On the long, pendulous 
peduncles, characteristic of the male tree, this 
plant produces its three types of flowers, 
staminate, pistillate, and hermaphrodite. The 
staminate are identical with those of the 
ordinary male tree and the pistillate with those 
of the female tree, but the hermaphrodite 
differ from those described above (form 3). 
These have a very much shortened corolla tube 
as in the case of the pistillate flower, the lobes 
being divided almost to the base of the ovary. 
On the edge of this short tube, quite near the 
base of the ovary, are attached only five 
stamens, and these are supplied with long 
filaments, which rest in furrows between the 
lobes of the ovary. These lobes are united at 
the base, but often separable at the upper ends. 
The resulting fruit is deeply furrowed. 
Form 7. Pentandria. This form produces 
hermaphrodite flowers of the same type as 
those just described (form 6). They have the 
corolla tube reduced to almost negligible 
length and the five stamens inserted on long 
filaments on this tube, near the base of the 
ovary. The ovary is deeply furrowed, with 
the stamens lying in the grooves between 
the lobes, thus giving rise to a deeply furrowed 
fruit. There are also staminate flowers of the 
ordinary type, and these are borne with the 
hermaphrodite.in short clusters as in the case 
of form 4, 
CHANGE OF SEX 
It is a fact worthy of note that some 
of these forms are not constant. One 
may assume the réle of another. Per- 
haps the most primary change of sex 
which takes place is to be observed in 
the appearance of hermaphrodite flow- 
ers on trees that have previously pro- 
duced only staminate inflorescence. 
That is, form 2 may pass into form 3 or 
form 6. Not only is it known that such 
changes take place, but the conditions 
which may bring them about have been 
under observation. This ‘‘fruiting of 
the male papaya’”’ takes place most 
freely in cool climates outside the 
tropics or at high altitudes. In Hawaii 
it may be seen that these trees fruit 
more abundantly on the mountains 
than near the sea level. In torrid 
climates the fruiting of the ‘‘male’’ is 
rare. It is to be remembered in this 
connection that all the staminate flow- 
ers of the male trees possess an unde- 
veloped or an abortive pistil. The only 
change in the cases mentioned consists 
in the development of this pistil, result- 
ing in a hermaphrodite flower. 
It is a matter of record that complete 
change of sex occasionally occurs when 
The Journal 
of Heredity 
the top is cut off from a purely stam- 
inate tree. Such treatment may result 
in the new tree top producing pistillate 
flowers exclusively, or the tree may 
become a hermaphrodite of the Elongata 
form. A tree of changed sex characters 
is shown in Fig. 13. It was formerly 
staminate and, being without fruit and 
useless to the owner, it was cut back to 
a stump and was used to suspend a back 
yard clothes line. Without any other 
known change in conditions it took on 
the fruit-bearing characters shown in 
the illustration and produced pistillate 
flowers exclusively on all of its branches. 
It is to be noted, however, that such 
changes take place with no certainty or 
regularity. At the Hawaii Experiment 
Station, the cutting back of a c-nsider- 
able number of staminate trees on some 
occasions has produced no difference in 
sex, while at other times a small per- 
centage of pistillate and of hermaphro- 
dite fruit-bearing trees have resulted. 
It is worthy of note that no record has 
been found by the writer in the litera- 
ture of the papaya which would indicate 
that the pistillate or female tree has ever 
changed its sex. 
ORIGIN OF THE HERMAPHRODITE 
Because the hermaphrodite form is 
of great importance from the stand- 
point of the breeder, as will be shown a 
little later, it may be interesting to 
inquire into its probable origin. It is 
apparent that the form Correae is only 
a slight departure from the ordinary 
male or staminate tree. Now com- 
paring Correae with the hermaphrodite 
Elongata, it will be observed that the 
hermaphrodite flowers on both trees 
are the same and produce fruit of the 
same elongated form, but the trees 
differ only in three minor particulars: 
(a) In Elongata the flower clusters are 
greatly shortened; (b) It produces 
larger fruits usually; and (c) Its stam- 
inate flowers do not produce fertile 
pollen. It would appear that Elongata 
has been derived from the ordinary male 
or staminate tree, through Correae, by 
an increase in the number of hermaphro- 
dite flowers and the shortening of the 
clusters and of the fruit stems. 
Very little effort has been made to 
